After cooking and deboning chicken, layer in the bottom of a 9 x 13" baking dish. Cover this with a layer of Doritos, a layer of cheese, and a layer of onion. Heat soup, broth, and tomatoes to boiling and pour over other ingredients. Bake at 350 degrees for about 30 minutes. This dish can be made ahead of time and quickly assembled just before baking time. ENJOY!